That's a much tighter spending margin than previous reporting periods. From July 1 to Sept. 30, Hagan's campaign spent $11.6 million, compared to just $2.7 million by Tillis.

But in total, fundraising and spending in the pivotal U.S. Senate race hews somewhat close to what we expect. The incumbent—Hagan—raises more, particularly from those relatively unbridled political action committees, better known as PACs.

However, with total spending in the race expected to surpass a galling $100 million, it's clear that outside spending groups—packed with the likes of the Koch brothers and Art Pope—are engaged.